Passengers hold 500 (bottom) rupee banknotes to buy train tickets at a railway booking counter in Allahabad, India, November 9, 2016. People are queuing up outside banks across India to exchange 500 and 1,000 rupee notes after they were withdrawn as part of anti-corruption measures. Indians will be able to exchange their old notes, which stopped being legal tender at midnight on Tuesday, for new ones at banks until 30 December. The surprise move is part of a government crackdown on corruption and illegal cash holdings. Banks were shut on Wednesday to allow them enough time to stock new notes. There are also limits on cash withdrawals from ATMs. The BBC's Yogita Limaye in Mumbai says there have been chaotic scenes outside many banks. (Photo by Danish Siddiqui/Reuters)

A pair of gloved hands are dwarfed by the furry paws of Boris the Polar Bear at the Point Defiance Zoo & Aquarium's animal health care hospital Saturday, February 23, 2013 in Tacoma, Washington. (Dean J. Koepfler/Tacoma News Tribune/MCT)

The Aurora Borealis seen across the sky in Lapland, Finland. The beautiful phenomenon was captured by photographer Marko Korosec on a trip to the arctic region of Lapland in Northern Finland. He used long exposures on his Canon DSLR to create the stunning images. (Photo by Marko Korosec/Barcroft Media)

A security guard walks past a giant Doctor Who poster at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)

In this third of seven sequential photos, Elian Gonzalez is held in a closet by Donato Dalrymple, one of the two men who rescued the boy from the ocean, right, as government officials search the home of Lazaro Gonzalez for the young boy, early morning, April 22, 2000, in Miami, Florida. Armed federal agents seized Elian Gonzalez from the home of his Miami relatives before dawn, firing tear gas into an angry crowd as they left the scene with the weeping 6-year-old boy. This photo won the Prize in 2001. (Photo by Alan Diaz/AP Photo)

Nasar, an Arabian horse, stands in the office of doctor Stephanie Arndt at her home on February 19, 2014 in Holt, Germany. Fearing for the horse's safety, Mrs. Arndt brought the horse into her house during the Xaver heavy storm back in December, and the horse now wanders through the house daily, inspecting details and looking for snacks. Mrs. Arndt says she doesn't mind, and though the horse never spends the night, it does occasionally take a nap in the house. (Photo by Patrick Lux/Getty Images)

Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

A Dalek, a Cyberman and a Silence invade the Melbourne Cricket Ground on February 2, 2012 in Melbourne, Australia. The Doctor Who Daleks this weekend are performing for the first time outside of the UK with the Melbourne Syphony Orchestra at Plenary Hall. (Photo by Scott Barbour/Getty Images for BBC Worldwide)